I think it's a little disingenuous to pretend there is nothing political about this rally, when it's being held 3 days before Election Day, when it's being held on the Washington Mall, home of political rallies, when the audience of the Daily Show and Colbert is overwhelmingly Democrat-leaning, when Ariana Huffington is busing people in, and when the whole thing appears to have been conceived as a response to Glenn Beck's rally in August (and Beck also claimed his rally was non political, btw).
Even if one believes it's non-political, I think it's reasonable to assume that 99 percent of the people attending will be unhappy if Republicans gain control of Congress. And despite being a Stewart/Colbert fan, that's where the whole thing kind of concerns me -- because while left-leaning hipsters will be traveling to Washington to have their ironic, comedic, self-affirming fun on the Mall, the Teabaggers will be back at the home, working completely unironically in their determined slow-witted fashion, on get-out-the-vote drives and all the rest. And guess which side is more likely to gain power next week.